Generally, a positioning image is necessary to determine a scanning range and a location of image reconstruction before an imaging system scanning a patient. And then the imaging system scans the parts to be examined of the patient to obtain original data for image reconstruction to generate a medical image.
Taking the Positron Emission Tomography/Computed Tomography (PET/CT) system as an example, before the system performs imaging scanning, usually the system performs a positioning scanning to the patient to obtain a CT positioning image, and then a scanning area (i.e., an area of interest) may be determined based on the positioning image by a user, as the area to be reconstructed. Refer to FIG. 15, which illustrates an exemplary positioning image obtained after scanning the area to be imaged. On the interface where the positioning image is displayed, a rectangular frame representing the scan area 10 is drawn on the positioning image by dragging a mouse by a user. After dragging, the scan area 10 is determined. Organs or issues to be examined may be in the scan area 10 and the system may perform scanning and reconstruction based on the scan area 10 thus the rest of the patient may be free from scanning.
The above-mentioned manual adjustment of the scan range setting has a lot of shortcomings. Firstly, to manually adjust the scope of the scan range is often not accurate enough, and thus produce unnecessary CT dose. Secondly, manually adjusting the scope of the scan range spends long time, resulting in the extension of the entire scanning process time and reducing the efficiency of the scan. Further, the extension of the scanning process may increase the patient's physical and psychological burden.